Top-seeded Sabine Lisicki of Germany survived a day on which five seeds were beaten, reaching the quarterfinals of the ASB Classic with a 7-6 (3), 3-6, 6-3 win over compatriot Mona Barthel on Wednesday.
After all eight seeds came through the first round, second-seeded Peng Shuai of China, No. 5 Julia Goerges of Germany, No. 6 Roberta Vinci of Italy, No. 7 Yanina Wickmayer and No. 8 Monica Niculescu of Romania were all bundled out in Wednesday's second round.
The 15th-ranked Lisicki had highs and lows in her match against Barthel, hitting 38 winners but mixing in six double faults and 66 unforced errors.
Lisicki's match was delayed by rain and her timing was disrupted by a swirling breeze on center court. She still showed her class by overcoming the frustration of losing the second set to then sweep the third in 35 minutes.
''It's great to have a challenge like that,'' Lisicki said. ''That's why we play tennis. ''Mona gave me a great match and it's good to have that challenge early in the year.''
Lisicki's quarterfinal opponent will be her compatriot Angelique Kerber, who beat the ailing Goerges 6-2, 6-3. Goerges said after her first-round win she had picked up an illness after arriving in New Zealand.
Third-seeded Svetlana Kuznetsova breezed past 19-year-old American Christina McHale 6-1, 6-1 despite a rain delay when she was leading 5-1 in the second set. The win was Kuznetsova's first over McHale in three meetings.
''I was playing well,'' Kuznetsova said. ''I did some unforced errors but, still, I think I completed my game plan and that's what I wanted tonight.''
Kuznetsova next plays Italy's Sara Errani, who beat former champion Wickmayer 4-6, 6-1, 6-1.
The 52nd-ranked Lucie Hradecka, a French Open doubles champion and member of the Czech Republic's Fed Cup-winning team, overpowered 17th-ranked Peng 6-4, 6-3 in 73 minutes.
Hradecka's power prevented Peng from settling into any rhythm and the Chinese player, now bound from Melbourne and the Australian Open, never looked at ease.
''My serve was working well,'' Hradecka said. ''I'm just so happy with this win and for the moment I can't believe I did it.''
Vinci was beaten 6-3, 6-4 by Elena Vesnina of Russia and Niculescu went down 6-0, 6-2 to Zheng Jie of China.